Malicious software (malware) generally refers to unwanted, hostile, or intrusive software that can be used to disrupt computer or network operations, collect private or sensitive information, or access private computer systems or networks. Malware can be in the form of executable code, scripts, active content, and other software. Example malware includes computer viruses, worms, Trojan horses, rootkits, keyloggers, spyware, adware, botnet command and control (C&C) related malware, and other unwanted, hostile, or intrusive software.
Security solutions (e.g., security devices or appliances, which can provide firewall solutions) can be used to safeguard against malware. For example, a firewall can identify and prevent the further spread of malware in a network.
A firewall generally protects networks from unauthorized access while permitting authorized communications to pass through the firewall. A firewall is typically implemented as a device or a set of devices, or software executed on a device, such as a computer or appliance, that provides a firewall function for network access. For example, firewalls can be integrated into operating systems of devices (e.g., computers, smart phones, tablets, or other types of network communication capable devices). Firewalls can also be integrated into or executed as software on servers, gateways, network/routing devices (e.g., network routers), or appliances (e.g., security appliances or other types of special purpose devices).
Firewalls typically deny or permit network transmission based on a set of rules. These sets of rules are often referred to as policies. For example, a firewall can filter inbound traffic by applying a set of rules or policies. A firewall can also filter outbound traffic by applying a set of rules or policies. Firewalls can also be capable of performing basic routing functions.